(1) Field of the Invention
The invention relates to a weighing device and a weighing method for a production machine and/or installation for determining the weight of individual piece goods or individual groups of piece goods within a production line with scales which have a weighing receptacle for two or more piece goods as well as a method of determining the weight of individual piece goods or individual groups of piece goods within a production line. More particularly the invention pertains to a method or a machine having an evaluation unit for determining the difference between two weight values in a machine or process in which a feeding device feeds two or more piece goods into a weighing receptacle for jointly weighing the two or more piece goods to provide a first weight value and where one of the two or more piece goods are successively removed from the weighing receptacle to provide a second weight value.
(2) Description of Related Art Including Information Disclosed Under 37 C.F.R. 1.97 and 1.98
Monitoring scales are frequently used in production machines or installations to check the weight of the piece goods produced. Monitoring scales such as this are used, for example, in DE 196 09 431 to weigh packages of products. In this device, individual piece goods are conducted by means of a weighing belt and weighed during transportation on the weighing belt. The product is then labeled by means of a downstream labeling unit, with the weight information being applied in particular. Devices of this type are commercially available as separate weighing and labeling machines and are usually attached to a delivery belt of a production machine or installation.
With this type of monitoring scales, the weighing device has to be matched to the format of the piece good to be weighed. The largest provided piece good to be weighed has to have space on the weighing belt, with the result that the dimensions of said weighing belt have to be correspondingly large. However, this means that the belt speed has to be correspondingly increased when weighing a small piece good in order to ensure sufficient product throughput.
Furthermore, for individual weighing purposes, it is necessary to separate the piece goods arriving from the production machine or installation, as a result of which the complexity and also the space requirement are increased.